Air-pump



P. KUEHN.

AIR PUMP- APPLICATION FILED 050.15. 1919.

.1 375,16 0 Patented Apr. 19, 1921. 4

UNITED STATES,

P'ATENT OFFICE.

,PAUL minim, or DENVER, COLORADO.

' AIR-PUMP.

cation, reference being had therein to the accompanying drawings.

This invention relates to pumps and more particularly to" air pumps or compressors "andits object is to provide a simple and efficient construction whereby high pressures may be secured with a minimum expend1ture of power for driving the pump,

and the parts are efiiciently cooled without the necessity forp'roviding water jackets or; other external cooling means.

A further object is toautomaticallyjregulate the pressure which will be delivered by the pump and to provide an air cushion behind the piston to cause the pump to discharge with an even flow and to hold opposed pistons in spaced relation, obviating the necessity for a rigid connection between the pistons and the crank, and reducing fr'ict1on. M

It is also an object of the invention to provide certain other new and useful features in the construction and arrangement of parts, all as hereinafter more fully described.

With the above and other ends in view, the invention consists in the matters hereinafter set forth, and more particularly pointedout in the appended claims, reference being had to the accompanying drawing, in which--- a igure 1 is a longitudinal horizontal section through a pump embodying the invention, and

- Fig. 2 is a side elevation of the pump in operative position and connected to an air pressure tank.

As shown in the drawing, 1 indicates suitable supporting brackets having bearings 2 at their upper ends for a crank shaft 3 which is secured in the bearings against rotation therein in any suitable manner as by set screws 4, The crank shaft 3 is formed with a crank 5-which, by being a part of the shaft 3, is also stationary being held against rotation by the shaft. Mounted upon the shaft 3 is a suitable crank case 6 for the crank 5 and to this crank case is secured, in any suitable manner, cylinders 7 extending Specification of Letters Patent.

Patented Apr. 19, 1921.

Application filed December 15, 1919. SeriaI No. 344,922.

digmetrically in opposite directions from th crank case 6. Within the cylinders 7 are suitable pistons 8 and these pistons are connected to the crank 5 by suitable'flexible connections 9, such as steel cables or othersuitable flexible members. The outer ends of the cylinders 7 are closed by heads 10 within which are suitable air inlet valves being provided with air outlet passages communicating with the chambers 14 and with suitable conduit pipes 16 leading longitudinally' of the cylinders to a suitable air chamber 17 formed in anextension orsleeve 18 on the crank case through which sleeve the shaft 3 extends.

ing gland 19 to prevent the escape of air longitudinally of the shaft from the chamber 17 and the shaft 3 is formedwith a longitudinal bore .20 communicating at its inner end with the chamber 17 to provide an airoutlet for said chamber. Connected to the outer end of the shaft 3 and forming a continuation ofthe passage 20, is a pipe 21 leading to an air tank 22 for the storage of compressed air delivered thereto by the pump. On the head or end of the crank case 6 opposite that which is provided withthe sleeve 18, is a tubular extension 23 fitting the shaft 3 and forming a bearing for the crank case upon the shaft. Secured in any suitable manner upon this tubular extension 23 is a pulley 24 by means of which power may be applied to the crank case to turn it and the cylinders 7 carried thereby about the crank shaft 3. The crank shaft is preferably formed with disk portions 25 to fit .within chambers provided therefor in the ends or heads of the crank case-6 and these disks are provided with peripheral grooves to receive packing1 rings 26 for'the purpose of making a ti t joint between the crank case heads and t e crank shaft so that air under compression introduced into the crank case and cylinders 7 between the pistons 8 therein, cannot escape along the crank-shaft 3 through the bearings of the crank case thereon. A check valve 27 is provided for the admission of air under pressure into the The-outer end of the sleeve 18 is provided with a suitable pack-,

cylinders and crankcase, said check valve bein located at any convenient point such as a jacent the inner end of one of the cylinders and the'casing 28 containing this check valve is provided with an air lnlet 'nipple 29 forthe attachment thereto of an air hose or' other suitable connection for delivering air under pressure to the casing 28, which air will be admitted through the check valve 27 into the inner ends of the cylinders and the crank case 6.

A heavy air pressure is thus maintained in the crank case and cylinders between the pis- -tons 8 to hold the pistons in spaced relation,

inders about the crank shaft will cause the piston and cylinders to move relatively in a longitudinal direction. This movement of the pistons within the cylinders relatively thereto will cause air to be drawn in through the inlet valves .11 and to be discharged through the valves. 12 and out through the pipes 16, conduit 20 and pipe 21 into the tank 22. Rapid rotation of the crank case and cylinders about the stationary crank shaft 3 will deliver a volume of a1r under pressure to the tank 22 and the extent of compression of this volume of air will be dependent upon the height of the coriipression' of-the air contained within the crank case and inner ends of the cylinders between the pistons 8. As soon as the compression in the tank rises to a point above that of the air cushion between the pistons, this air cushion will be compressed and the plstons will be moved toward the crank shaft to a' point concentric with the axis of said shaft,

sucha movement being permitted by the flexible connections 9 of the pistons with the crank 5. The cylinders will then rotate about the fixed crank shaft without relative movement between the pistons 8 and cylinders and the pumping action will be automatically discontinued until such time as the pressure upon the heads bf the pistons falls to'a point below the pressure of the air cush- -ion between said pistons.

By connecting the pistons .8 with their crank by means of the flexible connections 9, the pumping action of the pump is not only automatically stopped but side thrust and consequent friction of the pistons against the cylinder walls is obviated.

Further, the air cushion provided between the pistons to hold them in spaced relation also permits the pistons to yield under heavy pressure, providing an air cushion which allows the pistons to yield during their-impulse strokes and thus give an even continuous flow of air orother fluid which is being discharged under pressure bythe action of these pistons in their movements relative to the cylinders. p I

It will be understood that the device as shown in the drawing is merely illustrative of an embodiment of the invention and that changes in the construction and arrangement of parts may be made within the scope of the appended claims without departing from thespirit of the invention, and I do not therefore limit myself to theconstruction .shown.

Having thus fully described my invention, what I claim is:

1. In a device of the character described, the combination of a non-rotatable crank shaft, cylinders extending radially from and rotatable about the crank shaft, pistons within the cylinders, flexible connections connecting the pistons and a crank of the means for holding the piston spaced from the crank, said spacing being limited by said flexible connection.

3. Ina device of the character described, the combination of a non-rotatable crank shaft having a crank, an air ti ht crank case rotatable about the longitu inal axis of the crank shaft, a cylinder carried by and opening into the crank case, a piston inthe cylinder, and a flexible connection between the piston and crank of the crank shaft, said crank case and inner end' of said cylinder being adapted to contain air under a pressure for holding the flexible connection extended and the piston spaced from the crank of the crank shaft.

' 4. In a device of the characer described, the combination of a non-rotatable crank s haft having a crank, an air tight crank "case rotatable about the axisof the shaft,

opposed cylinders extending radially from the crank case with their inner ends opening into .the crank case, pistons in the cylinders, a flexible connection between each piston anfi said crank, and means for maintaining air under pressure within the crank case and inner ends of the cylinders between the pistons therein. p

' 5. In a device of the character described, the combination of a non-rotatable crank shaft having a crank, a crank case rotatable about the longitudinal axis of the shaft,

cylinders carried by the crank case and ex- 13*? tending radially therefrom and opening connections extended and the pistons in 10 into the crank case at their inner ends, pis-' spaced relation.

tons in the cylinders, means forming a flexi- In testimony whereof I afiix my signature ble connection between each plston and the in the presence of two witnesses.

ing the crank case and cylinders carried thereby, and means for maintaining an air iVitne'sses:

pressure within the crank case and inner ANNA MI. Dorm,

ends of the cylinders to hold the flexible CHAs. W. STAU'FFIGER.

crank of the crank shaft, means for rotat- PAUL 

